This invention relates to a method and system for the transmission of serial data, and more particularly to a method and system for the transmission of serial data that enable transmission errors and the breakage or disconnection of transmission lines to be detected in a reliable manner.
Data transmission systems which are widely known in the art have two data transmission paths, namely a sending line and a receiving line, over which serial data can be sent and received between two units in both directions in the form of a bit serial. If one unit is denoted the master and the other the slave, the master sends serial data to the slave over the sending line, and the slave transfers serial data to the master over the receiving line. Data transmission systems of this type frequently experience breakage or disconnection of transmission lines and transmission errors due to noise or the like, and such occurrences must be detected rapidly to preclude erroneous equipment operation.
Various systems have been put into practice to check for transmission errors. One such system adds a parity bit to the data. However, this does not permit a transmission error to be detected if the even-numbered bit in the received serial data has undergone a change in sign, nor does it permit detection of a break or disconnection in the transmission lines.